1. Field of the Invention
The present invention relates generally to systems which convert chemical energy into electrical energy and more particularly, in water electrolysis, to the control of the process water used in a fuel cell system including a fuel cell and electrolyzer.
2. Background Art
U.S. Pat. No. 4,657,829, describes a hydrogen/air fuel cell having a water electrolysis subsystem and gas storage system. The electrolysis subsystem comprises a plurality of bipolar cells. Water is introduced into the anode chambers of the electrolysis cells from liquid/vapor separators. Hydrogen and oxygen produced by the cells are fed to liquid/vapor separators. Excess water from the anode chamber and water pumped prototonically across the membrane with the hydrogen ions is separated from the gases with the gases being introduced into respective pressurized storage vessels. Each of the separators contain a float switch which actuates pumps and drain valves to feed water to the electrolyzer. As the oxygen and hydrogen in the pressure vessels are consumed, the pressure drops and a signal from the pressure transducers causes additional water to be electrolyzed to replinish depleated oxygen and hydrogen levels.
The electrolyzer system associated with a fuel cell stack described above is limited, however, by a multiplicity of switching and fluid flow control functions.
It is accordingly an object of this invention to provide a novel, variable pressure passive regenerative fuel cell system defined by an absence of complex operational components.
Other objects and advantages of this invention will become apparent from the following detailed description.